Quantum simulation of non-trivial topology

We propose several designs to simulate quantum many-body systems in manifolds with a non-trivial topology. The key idea is to create a synthetic lattice combining real-space and internal degrees of freedom via a suitable use of induced hoppings. The simplest example is the conversion of an open spin-ladder into a closed spin-chain with arbitrary boundary conditions. Further exploitation of the idea leads to the conversion of open chains with internal degrees of freedom into artificial tori and M\"obius strips of different kinds. We show that in synthetic lattices the Hubbard model on sharp and scalable manifolds with non-Euclidean topologies may be realized. We provide a few examples of the effect that a change of topology can have on quantum systems amenable to simulation, both at the single-particle and at the many-body level.Comment: 12 pages, 15 figure

Quantum simulation of an extra dimension

We present a general strategy to simulate a D+1-dimensional quantum system using a D-dimensional one. We analyze in detail a feasible implementation of our scheme using optical lattice technology. The simplest non-trivial realization of a fourth dimension corresponds to the creation of a bivolume geometry. We also propose single- and many-particle experimental signatures to detect the effects of the extra dimension.Comment: 5 pages, 3 figures, revtex style;v2 minor changes, references adde

Synthetic gauge fields in synthetic dimensions

We describe a simple technique for generating a cold-atom lattice pierced by a uniform magnetic field. Our method is to extend a one-dimensional optical lattice into the "dimension" provided by the internal atomic degrees of freedom, yielding a synthetic 2D lattice. Suitable laser-coupling between these internal states leads to a uniform magnetic flux within the 2D lattice. We show that this setup reproduces the main features of magnetic lattice systems, such as the fractal Hofstadter butterfly spectrum and the chiral edge states of the associated Chern insulating phases.Comment: 5+4 pages, 5+3 figures, two-column revtex; v2: discussion of role of interactions added, Fig. 1 reshaped, minor changes, references adde

Simulation of gauge transformations on systems of ultracold atoms

We show that gauge transformations can be simulated on systems of ultracold atoms. We discuss observables that are invariant under these gauge transformations and compute them using a tensor network ansatz that escapes the phase problem. We determine that the Mott-insulator-to-superfluid critical point is monotonically shifted as the induced magnetic flux increases. This result is stable against the inclusion of a small amount of entanglement in the variational ansatz.Comment: 14 pages, 6 figure

Divergent effects of Nitric oxide on airway epithelial cell activation

Nitric oxide (NO*) is a gaseous mediator synthesized by Nitric oxide sinthases. NO* is involved in the modulation of inflammation, but its role in airway inflammation remains controversial. We investigated the role of NO* in the synthesis of the chemok Nes Interleukin-8 and Monocyte Chemotactic Protein-1, and of Intercellular Adhesion Molecule-1 by human airway epithelial cells. normal human bronchial epithelial cells and the bronchial epithelial cell line BEAS-2B were used. Neterleukin-8 (IL-8) and Monocyte Chemotactic Protein-1 (MCP-1) secretion and Intercellular Adhesion Molecule-1 (ICAM-1) expression were measured by ELISA. mRNA was assessed by semiquantitative RTI-PCR. Neterleukin-8 secretion was significantly reduced after 24h incubation with the NO* donor, sodium nitroprusside. The effect was dose-dependent. Similar results were obta Ned with S-Nitroso-N-D,L-penicillam Ne and S-Nitroso-L-glutathione. Inhibition of endogenous NO* with the Nitric oxide synthase inhibitor N-Nitro-L-arg N Ne-methyl-esther caused an increase in IL-8 secretion by lypopolisaccharide- and cytok Ne-stimulated BEAS-2B cells. Sodium nitroprusside also caused a reduction in Monocyte Chemotactic Protein-1 secretion by both cell types. In contrast, Intercellular Adhesion Molecule-1 expression was upregulated by sodium NItroprusside. RTI-PCR results indícate that the modulation of protein levels was paralleled by modification in mRNA levels. NO* has divergent effects on the synthesis of different inflammatory mediators in human bronchial epithelial cells

Topological Wilson-loop area law manifested using a superposition of loops

We introduce a new topological effect involving interference of two meson loops, manifesting a path-independent topological area dependence. The effect also draws a connection between quark confinement, Wilson-loops and topological interference effects. Although this is only a gedanken experiment in the context of particle physics, such an experiment may be realized and used as a tool to test confinement effects and phase transitions in quantum simulation of dynamic gauge theories.Comment: Superceding arXiv:1206.2021v1 [quant-ph

Skin Cancers in Croatia, 2003–2005: Epidemiological Study

This study presents the incidence of major nonmelanoma skin cancers (major NMSCs), other nonmelanoma skin cancers (other NMSCs) and malignant melanoma (MM) in Croatia. The skin cancers recorded between 1 January 2003 and 31 December 2005 were retrospectively analyzed. Until 2003, the incidence of major NMSCs and other NMSCs was not estimated in Croatia. Incident cases of NMSCs were identified by the use of a questionnaire distributed to dermatology departments in Croatia and then collected at the University Department of Dermatology and Venereology, Zagreb University Hospital Center, and from the records kept at the National Cancer Registry. Incident cases of MM were extracted from the National Cancer Registry. During the 3-year period, 9,479 cases of major NMSCs are recorded, 4,622 (49%) in male and 4,857 (51%) in female patients. The crude incidence rate was 72.1/100,000 for males and 70.3/100,000 for females. Basal cell carcinoma (BCC) was the most common major NMSC in both sexes. In the total number of major NMSCs, there were 7,244 cases of BCC. Squamous cell carcinoma (SCC) was the second most common major NMSC. There were 1,860 SCC cases. The crude incidence rate was 54.9/100,000 for BCC in males, 53.9/100,000 in females, and 14.6/100,000 for SCC in male and 13.4/100,000 in female patients. Other NMSCs were registered in 119 cases (53% male and 47% female). The crude incidence rate was 0.9/100,000 for male and 0.8/100,000 for female patients. MM was registered in 1,427 cases (48% male and 52% female.) The crude incidence rate was 10.7/100,000 for males and females. These results will serve as reference for studying the patterns of descriptive epidemiology of major NMSCs, other NMSCs and MM in Croatia and Europe in the forthcoming years

Strigolactones affect phosphorus acquisition strategies in tomato plants

Strigolactones (SLs) are plant hormones that modulate morphological, physiological and biochemical changes as part of the acclimation strategies to phosphorus (P) deficiency, but an in‐depth description of their effects on tomato P‐acquisition strategies under P shortage is missing. Therefore, in this study, we investigate how SLs impact on root exudation and P uptake, in qualitative and quantitative terms over time, in wild‐type and SL‐depleted tomato plants grown with or without P. Under P shortage, SL‐depleted plants were unable to efficiently activate most mechanisms associated with the P starvation response (PSR), except for the up‐regulation of P transporters and increased activity of P‐solubilizing enzymes. The reduced SL biosynthesis had negative effects also under normal P provision, because plants over‐activated high‐affinity transporters and enzymatic activities (phytase, acidic phosphatase) to sustain elevated P uptake, at great carbon and nitrogen costs. A shift in the onset of PSR was also highlighted in these plants. We conclude that SLs are master kinetic regulators of the PSR in tomato and that their defective synthesis might lead both to suboptimal nutritional outcomes under P depletion and an unbalanced control of P uptake when P is available